San Juan Island National Historical Park
Fortifications and other 19th-century military installments commemorate the Pig War, in which the United States and Great Britain nearly went into battle over their respective claims on the San Juan Islands. The park comprises two separate areas on opposite sides of the island. English Camp, in a sheltered cove of Garrison Bay on the northern end, includes a blockhouse, a commissary, and barracks. American Camp, on the southern end, has a visitor center and the remains of fortifications; it stretches along driftwood-strewn beaches. Great views greet you from the top of the Mt. Finlayson Trail—if you're lucky, you might be able to see Mt. Baker and Mt. Rainier along with the Olympics. From June to August you can take guided hikes and see reenactments of 1860s-era military life.